Lead Sponsor: University of Pittsburgh

Collaborators: National Heart, Lung, and Blood Institute (NHLBI)

Intervention / Treatment: OTHER: Standard of care, BIOLOGICAL: Red Blood Cell

Lead Sponsor: caterina P minniti

Collaborators: Duke University

Intervention / Treatment: OTHER: Placebo, DRUG: Topical Sodium Nitrite

Lead Sponsor: Dana-Farber Cancer Institute

Collaborators: National Heart, Lung, and Blood Institute (NHLBI), Brigham and Women's Hospital, Medical College of Wisconsin, Boston Children's Hospital, Children's Hospital Medical Center, Cincinnati, Duke University, Washington University School of Medicine, UCSF Benioff Children's Hospital Oakland, Johns Hopkins University, Baylor College of Medicine, University of Illinois at Chicago, Wayne State University, La Jolla Institute for Allergy & Immunology

Intervention / Treatment: DRUG: Placebo, DRUG: Regadenoson